Statue of Ymir

Who are you to swear by Ymir? she mocked. What know you of the gods of ice and snow, you who have come up from the south to adventureamong an alien people? - Gods of the North

While individual Nordheimer clans may worship different minor deities, Ymir is considered the chief of all gods. The god of Storm and War is said to send his daughter Atali to fetch the souls of dead and dying warriors to fill the halls of Valhalla